Network devices communicate across a network (e.g., the Internet) in accord with many known protocols. One protocol, known as the Resource Reservation Protocol (the “RSVP protocol”), enables one or more network devices to reserve bandwidth based upon some pre-specified network policy. The policy may be based upon any desired characteristic, such as the identity of some given user (e.g., an executive of a corporation requesting data) or network device (the prior noted executive's computer), or the type of data being transmitted (e.g., video on demand).
When utilizing the RSVP protocol, a sending access device (e.g., a personal computer) first transmits a “path message” toward a receiving access device across the network. Among other things, the path message typically includes a request for a specified amount of bandwidth (e.g., a Quality of Service level), and some policy data (e.g., identity of sender, type of data, etc . . . ). A network device, such as a router, between the two access devices then receives the path message, and communicates with a policy server to determine some preliminary policy issues for the two access devices. For example, the policy server may indicate the broadest policy parameters that the two access devices may utilize. The router then forwards the path message to the receiving access device.
Upon receipt of the path message, the receiving access device responsively generates and transmits a reservation message toward the sending access device. Among other data, the reservation message typically includes data indicating the amount of bandwidth that the receiving access device can handle (within the amount requested in the path message), and other policy data. The router receives the reservation message before the sending access device receives such message. The router then communicates with the policy server once again, requesting that the policy server apply the policy to the information in the two messages. The policy server responsively applies the policy, and then forwards such applied policy to the router. Upon receipt from the policy server, the router forwards the applied policy to the sending access device. The sending access device then utilizes the applied policy to mark specified data packets transmitted between the two access devices. Intermediate network devices thus may process such data packets in accord with the applied policy.
In commonly used systems, one policy server is utilized with many routers. Accordingly, problems can arise when many users are indirectly utilizing a single policy server. Specifically, processing both the path message and the reservation message, as well as applying the policy to the specified data, can degrade network performance.